ASP.NET URL OF IMAGE does not exist

Question

I have created a blog with ASP.NET MVC 4.

The problem is when my url is not localhost I cannot see any pictures inside my Posts, because they get wrong url. The url of the post can be:

1.localhost/post/2015/4/name_of_post or

2.localhost/archive/name_of_post or

3.localhost/name_of_category/name_of_post ,

and inside the post is the picture.

The picture must have this

url:localhost/App_Files/Upload/name_of_image.jpg

but gets instead this

url:localhost/post/2015/4/App_Files/Upload/name_of_image.jpg or

localhost/archive/name_of_post or

localhost/name_of_category/App_Files/Upload/name_of_image.jpg.

If you use the right url you will see the picture in browser. I use tinymce to add pictures inside the the post when i create it. The picture is saved as file in the App_Files/Upload folder. The post is inserted in a row as html in sql database. I use this routeConfig

routes.MapRoute(
"Post",
"Archive/{year}/{month}/{title}",
new { controller = "Blog", action = "Post" }
);

and the uploadController is this:

using HotNews.ViewModels;
using System;
using System.Collections.Generic;
using System.Configuration;
using System.IO;
using System.Linq;
using System.Web;
using System.Web.Mvc;

namespace HotNews.Controllers
{
    public class UploadController : Controller
    {
        //
        // GET: /Upload/
        public ActionResult Index(string id)
        {
            //var url = HttpRuntime.AppDomainAppVirtualPath;
            var url = ConfigurationManager.AppSettings["BlogUrl"];
            return View(new UploadViewModel
            {
                baseUrl = url,
                track = id
            });
        }

        [HttpPost]
        public ActionResult UploadFile()
        {
            var file = Request.Files[0];
            if (file != null && file.ContentLength > 0)
            {
                var fileName = Path.GetFileName(file.FileName);
                var path = Path.Combine(Server.MapPath("~/App_Files/Upload"), fileName);
                file.SaveAs(path);
            }

            return RedirectToAction("Index");
        }

        public ActionResult ListFiles()
        {
            var fileData = new List<ViewDataUploadFileResults>();

            DirectoryInfo dir = new DirectoryInfo(Server.MapPath("~/App_Files/Upload"));
            if (dir.Exists)
            {
                string[] extensions = MimeTypes.ImageMimeTypes.Keys.ToArray();

                FileInfo[] files = dir.EnumerateFiles()
                                      .Where(f => extensions.Contains(f.Extension.ToLower()))
                                      .ToArray();

                if (files.Length > 0)
                {
                    foreach (FileInfo file in files)
                    {
                        // var baseurl = ConfigurationManager.AppSettings["BlogUrl"];
                        var relativePath = VirtualPathUtility.ToAbsolute("~/App_Files/Upload") + "/" + file.Name;

                        fileData.Add(new ViewDataUploadFileResults()
                        {
                            // url = baseurl+relativePath,
                            url = relativePath,
                            name = file.Name,
                            type = MimeTypes.ImageMimeTypes[file.Extension],
                            size = Convert.ToInt32(file.Length)
                        });
                    }
                }
            }

            return Json(fileData, JsonRequestBehavior.AllowGet);
        }
    }
}

Must I create an image hanndler?? Must I create a new routeconfig?? And what kind??